Process for Decreasing Environmental Pollutants in an Oil or a Fat, a Volatile Environmental Pollutants Decreasing Working Fluid, a Health Supplement, and an Animal Feed Product

ABSTRACT

The invention relates to a process for decreasing the amount of environmental pollutants in a mixture comprising a fat or an oil, being edible or for use in cosmetics, the fat or oil containing the environmental pollutants, which process comprises the steps of adding a volatile working fluid to the mixture, where the volatile working fluid comprises at least one of a fatty acid ester, a fatty acid amid, a free fatty acid and a hydrocarbon, and subjecting the mixture with the added volatile working fluid to at least one stripping processing step, in which an amount of environmental pollutant present in the fat or oil, being edible or for use in cosmetics, is separated from the mixture together with the volatile working fluid. The present invention also relates to a volatile environmental pollutants decreasing working fluid, for use in decreasing an amount of environmental pollutants present in a fat or oil, being edible or for use in cosmetics. In addition, the present invention relates to a health supplement, a pharmaceutical and an animal feed product prepared according to the process mentioned above.

TECHNICAL FIELD OF THE INVENTION

This invention relates to a process for decreasing the amount ofenvironmental pollutants in a mixture comprising a fat or an oil, beingedible or for use in cosmetics. The present invention also relates to avolatile environmental pollutants decreasing working fluid. In addition,the present invention relates to a health supplement, a pharmaceutical,a cosmetic product and an animal feed product prepared according to theprocess mentioned above.

BACKGROUND OF THE INVENTION

DDT (2,2 bis-(p-chlorophenyl)-1,1,1-trichloroethane) and its degradationproducts are today found almost everywhere in the global environment.Numerous studies also report on the accumulation of often relativelyhigh concentrations of environmental pollutants like PCB, dioxins andbrominated flame retardants, and pesticides like toxaphenes and DDT andits metabolites in the deposit of e.g. marine organisms. The hazard ofthese compounds for both humans and animals have caused a growingconcern about the content of toxic substances in food and food stuff.Consumption of dioxins above safe levels over a lifetime may result inan increased risk of cancer.

Food products that have no or reduced amounts of pollutants are gainingpopularity as well as an increasing share of the market. Consequently,removal or reduction of pollutants in food products have the potentialto substantially increase marketability and value.

The commercially important polyunsaturated fatty acids in marine oils,such as fish oil, are preferably EPA (eicosapentaenoic acid, C20:5n-3)and DHA (docosahex-aenoic acid, C22:6n-3). The full nomenclature ofthese acids according to the IUPAC system is: EPAall-cis-5,8,11,14,17-eicosapentaenoic acid, DHAall-cis-4,7,10,13,16,19-docosahexaenoic acid. For many purposes it isnecessary that the marine oils should be refined in order to increasethe content of EPA and/or DHA to suitable levels, or to reduce theconcentrations of, or even eliminate, certain other substances whichoccur naturally in the raw oil.

The fatty acids EPA and DHA are also proving increasingly valuable inthe pharmaceutical and food supplement industries in particular. It isalso very important for fish oils and other temperature sensitive oils(e.g. oils that contain long chain polyunsaturated fatty acids) to keepthe temperature in some of the processes as low as possible.

The demand for marine oils of high quality is increasing. This issueforces the fish oil industry to consider use of alternative refiningtechniques for fish oils with inferior quality, i.e. oils with highamounts of free fatty acids that make the oils less useful fornutritional purposes and make traditional alkaline refining morecomplicated and costly. If environmental pollutants can be successfullyremoved from such fish oils they are appropriate for use in the animalfeed industry, e.g. in animal feed products.

From the literature it is known that molecular distillation, or shortpath distillation as the technique alternatively may be named, can beused to remove the pesticides DDT and its metabolites from fish oil (K.Julshamn, L. Karlsen and O. R. Braekkan, Removal of DDT and itsmetabolites from fish oils by molecular distillation,Fiskeridirektoratets skrifter; Serie teknologiske undersokelser, Vol. 5No. 15 (1973)). A practical upper limit was 65% removal together with aloss of about 25% of vitamin A. In many industrial fish oil refiningprocesses a removal of DDT up to 65% is not satisfactory.

Anthony P. Bimbo: Guidelines for characterization of food-grade fishoil. INFORM 9(5), 473-483 (1998), reported that vacuum stripping orthin-film distillation can be used to remove chlorinated hydrocarbonsand free fatty acids from fats or oils. A disadvantage by using vacuumstripping to refine oils is that sufficient results only can be achievedthen the vacuum stripping process is carried out at a high temperature.Further, the high temperature gives rise to undesirable side reactions.

Jiri Cmolik og Jan Pokorny: Physical refining of edible oils, Eur. J.Lipid Sci. Technol. 102(7), 472-486 (2000) describes physical refiningof edible oils and the use of molecular distillation for removal ofundesirable substances in crude oils, preferably crude vegetable oils,respectively the use of steam stripping in order to remove free fattyacids from an oil composition. Physical refining is used to refine oilsof good quality, i.e. oils with small amounts of free fatty acids.However, physical refining is more complicated and costly for oils withinferior quality.

In WO 9524459 a process for treating an oil composition containingsaturated and unsaturated fatty acids in the form of triglycerides, inorder to obtain a refined product with higher concentrations of thepolyunsaturated fatty acids, is presented. This process also is intendedto be used for removal of some environmental pollutants from an oilcomposition, wherein the process comprises the steps of; subjecting theoil composition to a transesterification reaction and thereaftersubjecting the product obtained in the first step to one or moremolecular distillations. This technique has the severe limitation thatit can only be used for fish oils that have been partiallytransesterified using a lipase catalyst that discriminates againstomega-3 fatty acids. Obviously, this technique can not be used forcommercial fish oils.

In EP0632267 A1 a method of measuring the content of polycyclic aromatichydrocarbons(PAH) remaining in lanolin is presented. The European patentdocument also describes a method of removing PAH remaining in woolgrease or lanolin by a vacuum distillation of the grease or lanolinunder specified conditions either directly or after having been treatedwith a borate and, if necessary, obtaining various lanolin derivativesfrom the treated wool grease or lanolin. However, the techniquedescribed in said patent document requires very high temperatures (230°C.) in order to achieve 90% reduction in PAH content.

Another interesting observation is that the removal of environmentalpollutants from fats or oils is not a trivial matter. Several differenttechniques, some of which are mentioned above, to accomplish this taskhave been developed, but none of them is sufficiently effective andgentle to the fat or oil. In addition, it is nowadays a problem for e.g.the marine oil industry that the amounts of pollutants in e.g. fish oilbecome increased.

SUMMARY OF THE INVENTION

One object of the present invention is to offer an effective process fordecreasing the amount of environmental pollutants in a fat or an oil,being edible or for use in cosmetics.

According to a first aspect of the invention, this and other objects areachieved with a process for decreasing the amount of environmentalpollutants in a mixture comprising a fat or an oil, being edible or foruse in cosmetics, the fat or oil containing the environmentalpollutants, which process comprises the steps of adding a volatileworking fluid to the mixture, where the volatile working fluid comprisesat least one of a fatty acid ester, a fatty acid amide, a free fattyacid and a hydrocarbon, and subjecting the mixture with the addedvolatile working fluid to at least one stripping processing step, inwhich an amount of environmental pollutants present in the fat or oil,being edible or for use in cosmetics, is separated from the mixturetogether with the volatile working fluid. Herein, “an amount” isinterpreted to include decreasing of an amount up to 95-99% of someenvironmental pollutants, i.e. a substantial removal of specificpollutants and/or toxic components from a fat or oil composition.

The use of a volatile working fluid in a stripping process fordecreasing an amount of environmental pollutants in a mixture comprisinga fat or an oil, being edible or for use in cosmetics, containing theenvironmental pollutants, and/or toxic components, has a number ofadvantages.

An advantage of using a volatile working fluid in a process comprisingat least one stripping processing step is that an amount ofenvironmental pollutants in the mixture can more easily be stripped offtogether with the volatile working fluid, i.e. the environmentalpollutants present in the fat or oil mixture is separated from themixture together with the working fluid. Preferably this is possible aslong as the volatile working fluid is essentially equally or lessvolatile than the environmental pollutants that is to be removed fromthe fat or oil mixture. The stripped pollutants (components) and most ofthe volatile working fluid will be found in the distillate.

In addition, the use of a volatile working fluid comprising at least oneof a fatty acid ester, a fatty acid amide, a free fatty acid and ahydrocarbon in at least one stripping process step results in that useof the inventive process decreases the amount of dioxins in a fish oilwith more than 95%. By using the inventive process it is also possibleto decrease the amount of chlorinated organic pesticides (or pollutants)in a mixture comprising a fat or an oil, being edible or for use incosmetics, which pollutants are even less volatile than DDT, forinstance dioxines, toxaphenes and/or PCB.

Separation of such heavy and undesirable components from the fat or oilmixture according to the invention, using mild conditions that do notdecompose even very unsaturated oils, is surprising. Further, accordingto the present stripping process it is possible to decrease an effectiveamount of PAH at much lower temperatures compared to the techniquesknown from the prior art.

Another advantage of adding a volatile working fluid to an oil or fatmixture prior to a stripping process is that removal of free fatty acidsis facilitated, which will result in a higher quality of the oilproduct.

In addition, the volatile working fluid according to the inventionallows environmental pollutants or other toxic components to be strippedoff by e.g. molecular distillation even from oils of lower quality, i.e.oil for feed purposes. Further, the process according to the inventioncan also be used for decreasing the amount of toxic compounds in aricinus oil, preferably trace of ricinine(1,2-dihydro-4-methoxy-1-methyl-2-oxo-3-pyridinecarbonitrile). By usingthe process according to the invention the amount of ricinine may bedecreased with at least 80-90%.

In a preferred embodiment of the present invention the volatile workingfluid is an organic solvent or solvent mixture or a composition with asuitable volatility.

The volatile working fluid of the present invention is at least one of afatty acid ester, a fatty acid amide, a free fatty acid, bio-diesel anda hydrocarbon, also including any combinations thereof.

In another preferred embodiment the volatile working fluid comprises atleast one fatty acid ester composed of C10-C22 fatty acids and C1-C4alcohols, or a combination of two or more fatty acid ester each composedof C10-C22 fatty acids and C1-C4 alcohols. Preferably, the volatileworking fluid is at least one of amides composed of C10-C22 fatty acidsand C1-C4 amines, C10-C22 free fatty acids, and hydrocarbons with atotal number of carbon atoms from 10 to 40. Most preferably, thevolatile working fluid is a mixture of fatty acids from marine oils,e.g. fish body oil and/or fish liver oil, and/or ethyl or methyl estersof such marine fatty acids.

In another preferred embodiment of the process the volatile workingfluid is constituted by free fatty acids comprised in the fat or oil,being edible or for use in cosmetics, containing the environmentalpollutants, i.e. the fat or oil itself contains free fatty acids. Here,the free fatty acids in the oil or fat acts as the volatile workingfluid. Further, free fatty acids in an oil or fat also can contribute toan additive effect in a stripping process by partially acting as aninternal working fluid (or by being an active part of the working fluid)in the process. Such oils or fats mentioned above could e.g. be silageoils or oils that have been stored or transported for a long period oftime. This means that a volatile working fluid can be added to an oil orfat mixture prior to a stripping process and/or being comprised in thefat or oil mixture containing the environmental pollutants or toxiccomponents. In this way, the invention surprisingly is very efficientfor purifying oils that normally are classified as oils of low quality.

In another preferred embodiment of the stripping process, the volatileworking fluid is constituted by free fatty acids comprised in a mixtureof at least a marine oil, e.g. a fish oil, with a high content of freefatty acids (a low quality marine oil), wherein the free fatty acids inthe oil mixture acts as a working fluid.

Further, it is hereby possible to decrease the amount of environmentalpollutants and to reduce the amount of free fatty acids in the marineoil at the same time and in the same process.

In another preferred embodiment of the process, the fatty acid esters,fatty acid amides and free fatty acids are obtained from at least one ofvegetable, microbial and animal fat or oil. The fatty acid estersmentioned above can e.g. be a by-product from distillation of an ethylester mixture prepared by ethylation of preferably a fish oil. In theprocess industry trade with intermediates is increasing and opens up foran extra financial income.

In another preferred embodiment the volatile working fluid is obtainedfrom at least one of animal fat or oil, wherein the animal fat or oilpreferably is a marine oil e.g. a fish oil or an oil from other marineorganism e.g. sea mammals.

Further, in another preferred embodiment of the invention the fat oroil, being edible or for use in cosmetics, is obtained from at least oneof vegetable, microbial and animal fat or oil, or any combinationthereof. Preferably, the fat or oil, being edible or for use incosmetics, is a marine oil. Marine oils that have no or reduced amountsof environmental pollutants are gaining popularity as well as anincreasing share of the market. Consequently, removal or reduction ofpollutants in e.g. fish oils of high quality as well as fish oils withinferior quality have the potential to substantially increasemarketability and value. Therefore, in a more preferred embodiment ofthe invention the marine oil is obtained from fish or sea mammals,containing at least saturated and unsaturated fatty acids in the form oftriglycerides. It is important to note that the invention is not limitedto procedures were the working fluid is prepared from the same origin asthe oil that is being purified.

Additionally, the fat or oil, being edible or for use in cosmetics, mayalso be a ricinus oil for use in cosmetics or medicinal applications. Itis also of commercial interest to decrease the amount of pollutants ortoxic components in oil mixtures or blends comprising at least onemicrobial oil that e.g. will be used in food products or as foodsupplement (e.g. infant formula) preferable suitable for humans.

In another preferred embodiment of the invention the fat or oil, beingedible or for use in cosmetics, is a tocopherol concentrate preparedfrom a condensate from at least one deodorization process of at leastone vegetable oil, wherein the tocopherol concentrate containing atleast one of PAH and volatile pollutants, or any combination thereof.Commercially available tocopherol concentrate contains about 65-90%tocopherol and it will be apparent for one skilled in the art that thestripping process according to the invention may be used to separate anamount of environmental pollutants from a tocopherol concentrate.

In a preferred embodiment of the invention, the ratio of (volatileworking fluid):(fat or oil, being edible or for use in cosmetics) isabout 1:100 to 15:100. In a more preferred embodiment the ratio of(volatile working fluid):(fat or oil, being edible or for use incosmetics) is about 3:100 to 8:100.

In a preferred embodiment of the invention, said stripping process stepis carried out at temperatures in the interval of 120-270° C.

In a most preferred embodiment, the stripping processing step is carriedout at temperatures in the interval of 150-200° C. By adding a volatileworking fluid to the fat or oil mixture at this temperatures theinvention surprisingly shows that even termolabile polyunsaturated oilscan be treated with good effect, without causing degradation of thequality of the oil.

In another preferred embodiment, the stripping processing step iscarried out at a pressure below 1 mbar.

In another preferred embodiment, the stripping processing step is atleast one of a thin-film evaporation process, a molecular distillationor a short-path distillation, or any combination thereof. If at leastone stripping process step is a thin-film evaporation the process isalso carried out at mixture flow rates in the range of 10-300 kg/h m²,preferably 40-150 kg/h m². By using a stripping process, e.g. adistillation method, for decreasing the amount of environmentalpollutants in a fat or oil mixture comprising a volatile working fluidit is possible to carry out the stripping processes at lowertemperatures, which spare the oil and is at the same time favourable tothe end oil product.

In a preferred embodiment of the invention, the volatile working fluidis stripped off together with the environmental pollutants by at leastone short-path distillation or molecular distillation step. This ispossible as long as the volatile working fluid is essentially equally orless volatile than the environmental pollutants that are to be separatedfrom the fat or oil mixture.

In another preferred embodiment of the invention, the process allows theenvironmental pollutants to flash off most effective at processconditions of low temperatures and preferable high mixture flow rates.Further, this embodiment offers similar advantages as described above byusing the volatile working fluid.

In a preferred embodiment according to the invention the strippingprocess is carried out by a molecular distillation in the followingintervals; mixture flow rates in the interval of 10-300 kg/h-m²,temperatures in the interval of 120-270° C. and a pressure below 1 mbar.

In a most preferred embodiment of the invention the moleculardistillation is carried out at temperatures in the interval of 150-200°C. and at a pressure below 0.05 mbar.

In a further preferred process of the present invention, said process isa thin-film process that is carried out at 40-150 kg/h m² or at flowrates in the range of 400-1200 kg/h at a heated thin film area of 11 m²;36-109 kg/h-m². Please note, that the present invention can also becarried out in one or more subsequent stripping processing steps.

In another preferred embodiment of the present invention, for use indecreasing an amount of environmental pollutants and/or toxiccomponents, such as dioxins and/or PCB, present in a fat or oil, beingedible or for use in cosmetics, the working fluid is comprising at leastone of a fatty acid ester, a fatty acid amide, a free fatty acid and ahydrocarbon with essentially equally or less volatility compared to theenvironmental pollutants that are to be separated from the fat or oilmixture, or any combination thereof.

Preferably, the volatile environmental pollutants decreasing workingfluid is generated as a fractionation product. Additionally, thevolatile environmental pollutants decreasing working fluid is aby-product, such as a distillation fraction, from a regular process forproduction of ethyl and/or methyl ester concentrates. This by-productaccording to the invention can be used in a new process for decreasingthe amount of environmental pollutants in a fat or an oil. Morepreferably, the volatile environmental pollutants decreasing workingfluid, for use in decreasing an amount of environmental and/or toxiccomponents, present in a fat or oil, can be a by-product (a distillatefraction) from a regular process for production of ethyl esterconcentrates, wherein a mixture comprising an edible or a non-edible fator oil, preferably a fish oil, is subjected to an ethylating process andpreferably a two-step molecular distillation. In the two-step moleculardistillation process a mixture consisting of many fatty acids on ethylester form is separated from each other in; a volatile (light fraction),a heavy (residuum fraction) and a product fraction. The volatilefraction from the first distillation is distilled once more and thevolatile fraction from the second distillation process is then at leastcomposed of the volatile working fluid, preferably a fatty acid ethylester fraction. This fraction consists of at least one of C14 and C16fatty acids and at least one of the C18 fatty acids from the fat or oil,and is therefore also compatible with the edible or non-edible oil. Thefraction can be redistilled one or more times if that is deemed to besuitable. This prepared working fluid can then be used as a workingfluid in a new process for decreasing the amount of environmentalpollutants in a fat or an oil, wherein the edible or non-edible fats oroils and the oil or fat, being edible or for use in cosmetics, are ofthe same or different types.

In another embodiment of the invention a volatile working fluid may beproduced by subjecting fats or oils from an available source, forinstance fats or oils obtained from at least one of animal, microbial orvegetable origin, to an inter-esterification process, in which processthe triglycerides in the fats or oils are converted into esters ofaliphatic alcohols. Additionally, a bio-diesel and/or a mineral oil canbe used as a volatile working fluid. In the case when the volatileworking fluid is a biodiesel, it can be produced by a process, which isin common use for production of engine fuels (biodiesel), and thereforealso known by a man skilled in the art, which process comprises mixingthe fat or oil with a suitable amount of aliphatic alcohol, adding asuitable catalyst and heating the mixture for a period of time. Similaresters of aliphatic alcohols may also be produced by a high-temperaturecatalytic direct esterification process reacting a free fatty acidmixture with the appropriate aliphatic alcohol. The fatty acid estermixture produced in this manner may be used as a volatile working fluidas it is, but normally the conversion to esters of aliphatic alcohols isnot complete, the conversion process preferably leaving some un-reactednon-volatile glycerides in,the mixture. Additionally, some fats or oilsmay also contain certain amounts of non-volatile, non-glyceridecomponents (e.g. polymers). Such non-volatile components will preferablybe transferred to, and mixed with the final product, which product islow in environmental pollutants, when the fatty acid ester mixture isused as working fluid. A working fluid produced in this manner shouldtherefore be subjected to a distillation, preferably a molecular and/orshort path distillation, in at least one step, which distillationprocess generates a distillate more suitable to be used as a newvolatile working fluid.

In another preferred embodiment of the invention the volatile workingfluid comprises at least one of an ester and/or an amide composed ofshorter fatty acids and longer alcohols or amines, or any combinationthereof.

In a preferred embodiment of the invention, the volatile environmentalpollutants decreasing working fluid, for use in decreasing an amount ofenvironmental pollutants present in a fat or oil, being edible or foruse in cosmetics, is preferably a fatty acid ester (e.g. fatty acidethyl ester or fatty acid methyl ester), a fatty acid amide or freefatty acids obtained from at least one of vegetable, microbial andanimal origin, or any combination thereof. Preferably, said animalorigin is fish or sea mammals, i.e. that the volatile fat or oilenvironmental pollutants decreasing working fluid is obtained frommarine oils, e.g. from fish or from sea mammals. Further, in a preferredembodiment of the volatile environmental pollutants decreasing workingfluid, said fat or oil is edible for humans and/or animals or for use incosmetics.

In another embodiment of the invention, a volatile environmentaldecreasing working fluid according to the present invention, is used ina process for decreasing an amount of environmental pollutants, in amixture comprising a fat or oil, being edible or for use in cosmetics,preferably a marine oil, containing the unwanted components, in whichprocess the volatile working fluid is added to the mixture and then themixture is subjected to at least one stripping processing step,preferably a thin-film evaporation process, a molecular distillation ora short-path distillation, or any combination thereof, and in whichprocess an amount of toxic components present in the fat or oil, beingedible or for use in cosmetics, is separated from the mixture togetherwith the volatile working fluid.

In another preferred embodiment a health supplement, a pharmaceuticaland/or an animal feed product containing at least fat or oil (end)products, e.g. oil ingredient of fish feed, with a decreased amount ofenvironmental pollutants or toxic components, prepared according to atleast one of the previously mentioned processes is disclosed. For thepharmaceutical and food supplement industries, marine oils have to beprocessed in order to increase the content of EPA and/or DHA to suitablelevels and the removal or reduction of different kinds of pollutantshave the potential to substantially increase marketability and value.Therefore, the present invention also discloses a health supplement anda pharmaceutical respectively, containing at least a marine oil, such asfish oil, which marine oil is prepared according to the previouslymentioned process, in order to decrease the amount of environmentalpollutants in the marine oil.

In another embodiment of the invention the pharmaceutical and/or healthsupplement is preferably intended for treating cardiovascular diseases(CVD) and inflammatory diseases, but they also have positive effects onother CVD risk factors such as the plasma lipid profile, hypertensionand vascular inflammation. In more preferred embodiment of the inventionthe pharmaceutical and/or health supplement comprises at least one ofEPA/DHA ethyl esters and is intended for a range of potentialtherapeutic applications including; treatment of hypertriglyceridaemia,secondary prevention of myocardial infarction, prevention ofatherosclerosis, treatment of hypertension and/or kidney disease and toimprove children's learning ability.

Further, the present invention also disclose a marine oil product,prepared according to at least one of the previously mentionedprocesses. Preferably, the marine oil product is based on fish oil or afish oil composition.

In addition, there is a demand for marine oils of high quality. Thisissue forces the fish oil industry to consider alternative refiningtechniques. Further, by using one of the processes according to theinvention it is now possible to simultaneously decrease the amount ofenvironmental pollutants and/or to decrease the amount of free fattyacids in e.g. marine oils with inferior quality with a good result. Suchoils are appropriate to be used in e.g. animal feed products. If the oilor fat is constituted by high amounts of free fatty acids, said freefatty acids may act as the volatile working fluid in the strippingprocess.

In another preferred embodiment of the invention, an animal feedproduct, containing at least a marine oil, which marine oil is preparedaccording to one of the processes presented before, in order to decreasethe amount of environmental pollutants and/or the amount of free fattyacids in the marine oil. Preferably the animal feed product is a fishfeed product.

For companies producing tocopherol preparations it is of commercialinterest to refine their tocopherol concentrate from environmentalpollutants, especially PAH's (polycyclic aromatic hydrocarbons).Tocopherol is produced from condensate from deodorization of soy and/orpalm oil. Vegetable oils are deodorized preferably in the same way asfish oils, but at higher temperatures in order to distil off thetocopherols. Therefore, the condensate from the mentioned process alsocontains, except components causing bad taste and odour of the oil, highamounts of tocopherol. Further, this condensate is raw material in alltocopherol preparations that are so-called natural preparations.

In another preferred embodiment of the invention a tocopherolconcentrate product, based on a tocopherol concentrate prepared from acondensate from a deodorization process of at least one vegetable fat oroil, such as palm oil or soy oil, which concentrate contains at leastone of PAH and volatile pollutants, is prepared according to thestripping process of the present invention, in order to decrease theamount of environmental pollutants in the tocopherol concentrate. Theprocess for decreasing the amount of environmental pollutants and/orPAH's in a tocopherol concentrate, comprises the steps of adding avolatile working fluid to a tocopherol concentrate and subjecting theconcentrate, with the added volatile working fluid, to a strippingprocessing step, in which preferably PAH's are separated from theconcentrate with the volatile working fluid. The volatile working fluidmay be at least one of the working fluids mentioned before, or anycombinations thereof, and said stripping process step is carried out atprocess conditions mentioned before. In a embodiment of the inventionsaid stripping process step is carried out at a temperature in theinterval of 120-180° C. and at a pressure below 1 mbar. The ratio of(volatile working fluid):(tocopherol concentrate) is preferably about4:100 to 8:100.

For the cosmetic industry it is of commercial interest to refine ricinusoil from trace of toxic components.

It is valuable for this industry to market cosmetic products, such aslipstick, that are essentially free from toxic components, such asricinine. Ricinus oil is a vegetable oil produced from the seeds ofRicinus communis L., Euphorbiaceae. The oil is a triglyceride of fattyacids, with ricinoleic acid (d-12-hydroxyoleic acid) as the major fattyacid (approximately 87%). Due to the hydroxyl group of ricinoleic acid,ricinus oil can not be refined in traditional ways, i.e. by alkalirefining. Thus, traces of toxic components may not be easily removed.

Ricinine is a toxic nitrilpyridinone that might be present in the oil intrace amounts. Herein, the invention also disclose a cosmetic product,based on ricinus oil, which ricinus oil is prepared according to atleast one of the processes mentioned before, in order to decrease theamount of toxic components in the ricinus oil.

In another preferred embodiment of the invention the fat or oil is aricinus oil, for use in cosmetics or medicinal applications, and thepollutants that are to be separated according to the process of theinvention are toxic compounds, such as nitrilpyridinones.

In a preferred embodiment, the process for decreasing the amount oftoxic compounds in a ricinus oil, preferably trace of ricinine,comprises the steps of adding a volatile working fluid to a ricinus oilmixture and subjecting the mixture, with the added volatile workingfluid, to a stripping processing step, in which preferably traces ofricinine (from the ricinus oil) is separated from the mixture with thevolatile working fluid. The volatile working fluid may be at least oneof the working fluids mentioned before, or any combinations thereof. Ina more preferred process in order to decrease an amount of toxiccompounds in a ricinus oil, the stripping processing step is at leastone of a molecular distillation process, a thin-film evaporation processor a short-path distillation or any combination thereof, carried out attemperatures in the interval of 120-220° C., at a pressure below 0.1mbar. In the case of a thin-film evaporation process the process iscarried out at a mixture flow rate in the interval of 10-300 kg/h m².

In a most preferred embodiment of the invention, the ricinus oil mixturewas distilled at a temperature about 170° C., a pressure around 0.001mbar respectively a mixture flow rate about 150 kg/h-m². Up to 95% ofthe amount of ricinine present in the start oil may be removed with thestripping process according to the invention.

DEFINITIONS

As used herein the term environmental pollutants preferably means toxiccomponents and/or pesticides like polychlorinated biphenyls (PCB), DDTand its metabolites, organic compounds found in the sea environment andidentified as potentially harmful and/or toxic; Polychlorinatedtriphenyls (PCTs), dibenzo-dioxins (PCDDs), and dibenzo-furans (PCDFs),Chlorophenols and hexachloro-cyclohexanes (HCHs), toxaphenes, dioxins,brominated flame retardants, polyaromatic hydrocarbons (PAH), organictin-compounds (e.g. tributyltin, triphenyltin) and organicmercury-compounds (e.g. Methyl-Mercury).

As used herein the term oil and fat means fatty acids in at least one ofthe triglyceride and phospholipid forms. Generally, if the startmaterial in the stripping process is a marine oil, the oil may be any ofraw or partially treated oil from fish or other marine sources and whichcontains fatty acids, including polyunsaturated fatty acids, in the formof triglycerides. Typically, each triglyceride molecule in such a marineoil will contain, more or less randomly, different fatty acid estermoieties, be the saturated, monounsaturated or polyunsaturated, or longchain or short chain. Further, examples of vegetable oils or fats arecorn oil, palm oil, rapeseed oil, soybean oil, sunflower oil and oliveoil.

Further, the fat or oil may be pre-processed in one or several stepsbefore constituting the start material in the stripping process asdescribed above. An example of such a pre-processing step is adeodorization process. It 10 shall also be noted that the fat or oil maybe edible in one or several such pre-processing steps and/or in theprocessing steps according to the invention.

As used herein the term edible means edible for humans and/or animals.Additionally, as used herein the term “for use in cosmetics” means anoil or a fat that can be used in products that contributes to enhancehumans appearance and/or health, e.g. cosmetic and/or beauty careproducts.

As used herein the term working fluid is interpreted to include asolvent, a solvent mixture, a composition and a fraction, e.g. afraction from a distillation process, that has a suitable volatility,comprising at least one of esters composed of C10-C22 fatty acids andC1-C4 alcohols, amides composed of C10-C22 fatty acids and C1-C4 amines,C10-C22 free fatty acids, mineral oil, hydrocarbons and bio-diesel.

As used herein the term essentially equally or less volatile isinterpreted to include that the volatile working fluids having asuitable volatility in relation to the volatility of the environmentalpollutants that is to be stripped off from a fat or oil mixture.Further, commonly this is the case when the volatility of the workingfluid is the same or lower than the volatility of the environmentalpollutants. However, the term essentially equally or less volatile isalso intended to indude the case when the volatile working fluid issomewhat more volatile than the environmental pollutant.

Further, as used herein the term stripping is interpreted to include ageneral method for removing, separating, forcing or flashing off gaseouscompounds from a liquid stream. In addition, the term “strippingprocessing step” preferable herein is related to a method/process fordecreasing the amount of environmental pollutants in an oil or fat byone or more distilling or distillation processes, e.g. short pathdistillations, thin-film distillations (thin-film stripping or thin-film(steam) stripping), falling-film distillations and moleculardistillations, and evaporation processes.

As used herein the term “oils with a low quality” preferably means thatthe oil contains high amounts of free fatty acids, that makes them lessuseful for nutritional purposes and that traditional alkaline refiningin such oils is complicated and costly. Additionally, as used herein,the term mineral oil is interpreted to indude mineral oil products suchas e.g. fractions from distillation processes and white spirit. As usedherein hydrocarbons is interpreted to include organic compounds, thatare relatively large molecules composed mainly of carbon and hydrogen.They can also include nuclei of nitrogen, phosphorus, sulphur, andchlorine, among others.

As used herein bio-diesel means a commercial product (or products underdevelopment) used as an environment friendly alternative to fuel forcars comprising e.g. methyl esters from preferable vegetable or animaloils.

As used herein the term marine oils includes oil from fish, shellfish(crustaceans) and sea mammals. Non limiting examples of fish oils aree.g. Menhaden oil, Cod Liver oil, Herring oil, Capelin oil, Sardine oil,Anchovy oil and Salmon oil. The fish oils mentioned above may berecovered from fish organs, e.g. cod liver oil, as well as from the meatof the fish or from the whole fish.

As used herein the term health supplement is interpreted to include foodand food supplement to animals and/or humans, fortification of food,dietary supplement, functional (and medical) food and nutrientsupplement.

As used herein the term “treating” means both treatment having a curvingor alleviating purpose and treatment having a preventive purpose. Thetreatment can be made either acutely or chronically. Herein the termanimal feed product means food or food supplement specially to animalse.g. fish, fowls, pigs and furred (fur-bearing) animal.

As used herein the term fish feed product also includes a fish larvaefeed product.

As used herein the term microbial oils also includes “single cell oils”and blends, or mixtures, containing unmodified microbial oils. Microbialoils and single cell oils are those oils naturally produced bymicroorganisms during their lifespan.

Further, a fat or an oil, being edible or for use in cosmetics,according to the invention can also be a blend of e.g. microbial oils,fish oils, vegetable oils, or any combination thereof.

As used herein the term free fatty acids means fatty acids in free acidform. The free fatty acids is operative as a volatile working fluidand/or included in the fat or oil, being edible or for use in cosmetics.

As used herein the term “together with”, means that the volatile workingfluid will be stripped off together with, combined with, or adhering thepollutants, namely that the pollutants will accompany the working fluid.

As used herein the term acid value of a fat or an oil means the amountof free acids presented in a fat or an oil equal to the number ofmilligrams of potassium hydroxide needed to neutralize one gram of theoil, i.e. that the term serves as an index of the efficiency ofrefining. This means that a high acid value is characteristic for lowquality oil or fat products.

While the invention has been described in detail and with reference tospecific embodiments thereof, it will be apparent for one skilled in theart that various changes and modifications, i.e. other combinations oftemperatures, pressures, and flow rates during the stripping process canbe made therein without departing from the spirit and scope thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

The advantages and details of the present invention will become apparentfrom the following description when taken in conjugation with theaccompanying drawings, in which;

FIG. 1 is a schematic flow chart of one embodiment illustrating a methodfor decreasing the amount of environmental pollutants in a fat or anoil, being edible or for use in cosmetics, by adding a volatile workingfluid prior to a molecular distillation.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

A number of preferred embodiments of the process for decreasing theamount of environmental pollutants in a mixture comprising a volatileworking fluid and a fat or an oil, being edible or for use in cosmetics,containing environmental pollutants will be disclosed below.

A first embodiment of a process for decreasing the amount ofenvironmental pollutants in a fat or an oil, being edible or for use incosmetics, by adding a volatile working fluid prior to a moleculardistillation is presented in FIG. 1. The starting fat or oil, beingedible or for use in cosmetics, in the first embodiment of the inventionis a fish oil whether freshly refined, reverted or mixtures thereofcharacterized by a level of environmental pollutants. The exact amountof environmental pollutants varies depending upon such factors as fishspecies, seasonality, geographical catch location and the like.

As used herein the term molecular distillation is a distillation processperformed at high vacuum and preferably low temperature (above 120° C.).Herein, the condensation and evaporation surfaces are within a shortdistance from each other, so as to cause the least damage to the oilcomposition. This technique is also called short-path distillation, andcommercial equipment is readily available.

The molecular distillation plant (1) illustrated in FIG. 1, comprises amixer (2), a pre-heater (3), a degasser (4), a distillation unit (5) anda vacuum pump (6). In accordance to this embodiment, a volatile workingfluid comprising an ethyl ester fraction (6% relative to the oil) isadded to a fish oil mixture and blended in a mixer (2). The oil mixtureis then optionally passed through a means (3) for controlling the oilfeed rate (herein about 400 kg/h), such as an ordinary throttling valve.The fish oil mixture is then preheated with a heating means (3) such asa plate heat exchanger to provide a preheated fish oil mixture. Themixture is then passed through a degassing step (4) and admitted intothe molecular path distance evaporator (5), a tube (7) including thecondensation (8) and evaporation (9) surface.

The stripping process is carried out at a pressure between 0.1 and 0.001mbar and at a temperature of about 200° C. The fish oil mixture to beconcentrated is picked up as it enters the tube (7 a) by rotatingblades. The blades extend nearly to the bottom of the tube and mountedso that there is a clearance of about 1.3 mm between their tips and theinner surface of the tube. In addition, the blades are driven by anexternal motor. The fish oil mixture is thrown against the tube wall andis immediately spread into a thin film and is forced quickly down theevaporation surface. The film flows down by gravity and becomesconcentrated as it falls. Heated walls and high vacuum strips off thevolatile working fluid together with the environmental pollutants, i.e.the more volatile components (distillate) is derived to the closelypositioned internal condenser (8), the less volatile components(residue) continues down the cylinder. The resulting fraction, thestripped fish oil mixture containing at least the fatty acids EPA andDHA is separated and exit through an individual discharge outlet (10).

In a second embodiment a falling film evaporator is used. In fallingfilm evaporators liquid and vapours flow downwards in parallel flow. Theliquid to be concentrated, herein the fish oil mixture, is preheated toboiling temperature. The oil mixture enters the heating tubes via adistribution device in the head of the evaporator, flows downward atboiling temperature, and is partially evaporated. This gravity-induceddownward movement is increasingly augmented by the co-current vapourflow.

Falling film evaporators can be operated with low temperaturedifferences between the heating media and the boiling liquid, and theyalso have short product contact times, typically just a few seconds perpass.

In a third embodiment of the invention the process is carried out by ashort path distillation, which includes the use of a short pathevaporator that integrates the features and advantages of thin film orwiped film evaporators but adds internal condensing for applications.Short path evaporators are widely used in fine and specialty chemicalsfor thermal separation of intermediates, concentration of high valueproducts, and molecular distillation under fine vacuum conditions. Theirkey features make them uniquely suitable for gentle evaporation andconcentration of heat sensitive products at low pressures andtemperatures.

It should be understood that many modifications of the above embodimentsof the invention are possible within the scope of the invention such asthe latter is defined in the appended claims.

EXAMPLES

The invention will now be illustrated by means of the followingnon-limiting examples. These examples are set forth merely forillustrative purposes and many other variations of the process may beused. The examples below summarizes some results from differentpurification of fish oils by molecular distillation.

Equipment and Conditions for Laboratory Experiments

In example 1-3 below decachlorobiphenyl, 0.60 mg/kg, was added to a fishoil composition as a pollutant model substance. The high chlorinecontent in decachlorobiphenyl ensures that this compound is lessvolatile than environmental pollutants like PCB, DDT and its metaboites,toxaphenes, dioxins and brominated flame retardants.

Unless otherwise stated, in all the examples the pressure was 0.001mbar. However, as this is the lower limit of the pressure indicator, thereal pressure will vary. That is the reason for somewhat varying resultsfrom one example to the next. When the distillation equipment is runningunder stable conditions, no significant variations are expected.However, this points out that constant pressure is not a very strongcondition for carrying out the present invention.

Example 1 The Effect of Adding a Working Fluid

A fish oil composition containing fatty acids on triglyceride form anddecachlorobiphenyl (0.60 mg/kg), with or without a working fluid, hereinan ethyl ester, 8% relative to fish oil, (the ratio of (volatile workingfluid):(fish oil) is about 8:100) was distilled by a laboratory scalemolecular distillation at a rate of 600 ml/h and a temperature of 180°C. The used ethyl ester mixture was a by-product (distillate fraction)from production of EPA and DHA ethyl ester concentrates.

TABLE 1 The effect of adding a volatile working fluid DecachlorobiphenylDecachlorobiphenyl (mg/kg) (% of start value) Without WF 0.43 72 With WF0.022 3.7 *WF = working fluid

The results in table 1 show that addition of a volatile working fluid toa fish oil composition has a surprisingly and dramatic effect on theremoval of decachlorobiphenyl. Here, more than 95% of the amount ofdecachlorobiphenyl has been removed (“stripped” off) from the fish oilmixture by molecular distillation.

Example 2 The Effect of Different Flow Rates

A fish oil composition containing fatty acids in triglyceride form anddecachlorobiphenyl (0.60 mg/kg) was added a working fluid in the form ofa ethyl ester fraction in the same way as in example 1. The oil mixturewas then stripped by a molecular distillation carried out at differentflow rates, but at the same temperature (180° C.).

TABLE 2 The effect of different flow rates Flow rate (ml/h)Decachlorobiphenyl (mg/kg) 400 0.02 600 0.05 1000 0.20

The results given in the table above show that decachlorobiphenyl (andother volatile pollutants) will be flashed off (reduced) moresuccessfully at lower flow rates. However, the results of optimising theflow rates are less important compared to the effect of adding a workingfluid, such as a solvent, solvent mixture or a fraction containing anethyl ester.

Example 3 The Effect of Different Temperatures

Here, an ethyl ester fraction was added to a fish oil compositioncontaining decachlorobiphenyl (0.60 mg/kg) in the same way as inexample 1. The oil mixture was then stripped by molecular distillationat different temperatures.

TABLE 3 The effect of different temperatures Temperature (° C.)Decachlorobiphenyl (mg/kg) 180 0.11 200 0.04

Table 3 illustrates that an increased temperature gives an improvedremoval of pollutants, when a volatile working fluid has been added tothe oil mixture prior to a molecular distillation. Further, it isimportant to know that polyunsaturated fatty acids in fish oil arethermo-labile compounds and an increase in temperature is onlyapplicable within strict limits.

For a person skilled in the art it is obvious that the same effect asdescribed in example 1-3 will be achieved according to the invention byusing other volatile working fluids, as long as the working fluids areessentially equally or less volatile than the environmental pollutantsthat is to be separated from the oil or fat mixture.

Example 4 Sardine Oil—Industrial Full Scale Process

This example shows an industrial scale process for decreasing the amountof pollutants in a fish oil mixture, which process comprises a step ofadding a volatile working fluid to the fish oil mixture prior to amolecular distillation. 63.9 tons of a sardine oil containing differentenvironmental pollutants was added a volatile working fluid in the formof a fatty acid ethyl ester mixture (ethyl ester of fish oil (8%))before subjecting it to a molecular distillation process. The moleculardistillation process was then carried out at a temperature of 200° C., apressure of 0.04 mbar and a mixture flow rate of 300 l/h with a heatedsurface of 3 m².

After treatment, 61.0 tons of purified product were collected. Theresults in table 4 show the content of vitamin A(trans-retinol),cholesterol, toxaphenes and dioxins in the sardine oil before and afterstripping respectively.

TABLE 4 Toxaphenes and dioxins in a sardine oil before and afterstripping Before stripping After stripping Vitamin A 15.3 mg/g  13.0mg/g Cholesterol 3.6 mg/g 1.31 mg/g Toxaphenes 0.3 mg/g <0.1 mg/gDioxins 4.1 pg/g 0.34 pg/g

The results confirm that adding a working fluid to an oil beforestripping is effective in reducing the amounts of volatile pollutants atthe same time as the concentration of vitamin A, a valuable component inmany fish oils, is not seriously affected. This means that thispurification method can be used for products that contains vitamin A,e.g. cod liver oil.

In some cases a certain cholesterol level can be of value for someapplications of fish oils e.g. for fish feed, especially feed for fishlarvae. In these applications it is important to perform a preferentialremoval only of pollutants.

Example 5 Fish Oil Mixture—Industrial Full Scale Process

This example also shows an industrial full scale process for decreasingthe amount of pollutants in a fish oil, which process comprises thesteps of adding a volatile working fluid to the fish oil mixture andsubjecting the mixture, with the added volatile working fluid, to amolecular distillation processing step, in which environmentalpollutants present in the fish oil is separated from the mixture withthe volatile working fluid.

30 tons of a fish oil mixture containing different environmentalpollutants (see FIG. 2) was added a volatile working fluid in the formof an fatty acid ethyl ester mixture (ethyl ester of fish oil (6%))before subjecting it to a molecular distillation process. The moleculardistillation process was then carried out at a temperature of 200° C., apressure of 0.005 mbar and a mixture flow rate of 400 kg oil/h with aheated surface of 11 m².

After treatment, 29.5 tons of purified product were collected. Theresults are shown in FIG. 2. The results confirms that the content ofenvironmental pollutants in the fish oil mixture was strongly reducedafter the stripping process according to the invention. For instance,the content of PCB in the fish oil mixture was reduced with about 98%,the content of PCDD was reduced with approximately 80%, the content ofPCDF with about 95% and the amount of hexachlorocyclohexane respectivelyTE-PCB was almost negligible after stripping. For a person skilled inthe art it is obvious that the same effect may be achieved according tothe invention by using a volatile working fluid for decreasing an amountof pollutants in some other fat or oil compositions.

Example 6 Salmon Oil

In this example oil from fresh by-products from Atlantic salmon wasprocessed according to the invention. The process according to theinvention comprises the steps of adding a volatile working fluid to theoil mixture and further subjecting the mixture, with the added volatileworking fluid, to a molecular distillation processing step. 8% workingfluid (the ratio of (volatile working fluid):(salmon oil) is here about8:100) was added to the oil and the distillation process was performedat a pressure of 1×10⁻³ mbar, at a temperature of 180° C. and at amixture flow rate of 600 ml/hour.

Samples of the oil mixture was analysed before and after distillationrespectively, regarding the amount of brominated flame retardants, PCBsand some chlorinated pesticides, see the tables 5 and 6 below.

TABLE 5 Brominated flame retardants, μg/kg, before and after adistillation process Brominated flame retardants, μg/kg Before treatmentAfter distillation BDE 28 0.3 <0.2 BDE 47 5.3 <0.2 BDE 66 0.4 <0.2 BDE71 <0.2 <0.2 BDE 75 <0.2 <0.2 BDE 77 <0.2 <0.2 BDE 85 <0.2 <0.2 BDE 991.2 <0.2 BDE 100 1.0 <0.2 BDE 119 <0.2 <0.2 BDE 138 <0.2 <0.2 BDE 153<0.2 <0.2 BDE 154 0.5 <0.2 BDE 183 <0.2 <0.2 BDE 190 <0.2 <0.2 Me-TBBP-A0.2 <0.2 HBCD <1.1 <1.2

TABLE 6 PCB and chlorinated pesticides, μg/kg, before and afterdistillation PCB and chlorinated pesticides, (μg/kg) Before treatmentAfter distillation CB 28 <3 <3 CB 52 5 <3 CB 101 11 <7 CB 118 <9 <9 CB153 16 <7 CB 105 <3 <3 CB 138 13 <7 CB 156 <3 <3 CB 180 4.8 <4 Dieldrin22 <4 Endrin <3 <3 HCB 12 <1 α-HCH 3.8 <1 γ-HCH 5.3 <1 β-HCH <5 <6β-HEPO <2 <3 p,p′-DDE 38 <3 p,p′-DDD 15 <3 p,p′-DDT nd = not detected <8

It is observed that the invention removes almost all of the analysedenvironmental pollutants to a level below the analytical detectionlimit.

Additionally, for a person skilled in the art it will be obvious thatthe same procedure could be used for other marine oils, for example codliver oil or fish oil intended to be used as a component of feed forfarmed fish. Nowadays, commercial fish feed contains high amounts ofpollutants and it is therefore of large interest to decrease the amountsof toxic components in the current marine oil before the oil is added tothe feed.

Example 7 Removal of PAH's

In this example benzo[a]pyrene (8.36 μg/kg oil) was added to a fish oilcomposition, that already had been treated according to the invention,in order to remove environmental pollutants. The fish oil compositioncontaining the added benzo[a]pyrene was processed in a similar way andwith the same distillation equipment as described in example 1. Avolatile working fluid in the form of a fatty acid ethyl ester mixture,8% working fluid relative to the fish oil, was added to the fish oilcomposition, before subjecting the composition to a moleculardistillation process. The molecular distillation process was carried outat a temperature of 180° C., a pressure of 1·10⁻³ mbar, and a mixtureflow rate of 600 ml oil/h. The concentration of benzo[a]pyrene wasanalysed before processing and after processing, see table 7.

TABLE 7 The amount of benzo[a]pyrene before and after processing Beforeprocessing After processing Benzo[a]pyrene 7.9 0.77 (μg/kg)

The results given in the table above show that benzo[a]pyrene will beflashed off successfully according to the invention. In this example theconcentration of benzo[a]pyrene was reduced with about 90%.

This confirms that adding a volatile working fluid to a fat or an oilcomposition, at least containing polycyclic aromatic hydrocarbons(PAH's), before a stripping process according to the invention iseffective in separating an amount of PAH's from the start fat or oilcomposition together with the volatile working fluid.

Example 8

A working fluid consisting of ethyl esters of fish oil (8%) was added toan oil produced from farmed salmon. A distillation process was carriedout under the same conditions as in example 1 and a distillate fractionof 8.3% was collected. The acid value of the residual oil was reducedfrom 0.4 mgKOH/g before distillation to 0.1 mgKOH/g after distillationand the oil was analysed for contaminants before and after processing.

TABLE 8 Salmon oil. Content of Indicator-PCBs (μg/kg) before and afterprocessning. CB- CB- CB- CB- CB- CB- CB- CB- CB- 28 52 101 118 153 105138 156 180 Before <3 5 11 <9 16 <3 13 <3 4.8 After <3 <3 <7 <9 <7 <3 <7<3 <4

TABLE 9 Salmon oil. Content of organochlorine pesticides (μg/kg) beforeand after processing a- y- b- b- Dieldrin Endrin HCB HCH HCH HCH HEPOpp_DDE pp_DDD pp_DDT Before 22 <3 12 3.8 5.3 <6 <3 38 15 <8 After <4 <3<1 <1 <1 <6 <3 <3 <3 <8

The results show that adding a volatile working fluid prior to astripping (distillation) process is effective in decreasing the amountof organo-chlorine pesticides in a fish oil composition. In addition,the volatile working fluid also facilitates removal of free fatty acidsin the oil. Therein the acid value was decreased with 75%, i.e. from 0.4to 0.1. It is hereby possibly to decrease the amount of environmentalpollutants and to reduce the amount of free fatty acids in an oil or afat at the same time and in the same process.

Example 9 Removal of Free Fatty Acids

A fish oil purchased for production of fish feed was distilled by amolecular distillation process under the same conditions as given inexample 1 and the start oil had an acid value of 6.8 mgKOH/g. Afterremoval of a distillate corresponding to 4.3% by weight, the acid valueof the residual oil was reduced to 0.2 mgKOH/g and the amount ofenvironmental pollutants in the start oil was decreased.

In an identical distillation procedure, an oil with an acid value of20.5 mgKOH/g was distilled. After removal of a distillate of 10.6% theacid value was reduced to about 1.0 mgKOH/g and the amount ofenvironmental pollutants in the start oil were decreased.

Due to the fact that the stripping process in example 8 also facilitatesremoval of free fatty acids in the oil and that the free fatty acids arevolatile it can be expected that even oils with a low quality, i.e. ahigh content of free fatty acids, can be treated successfully accordingto the invention. An example of oils with low quality is silage oils oroils that have been stored or transported for a long period of time.Fish oils with low quality may be used for production of fish feed.

This example therefore shows that a stripping process for decreasing theamount of environmental pollutants in a mixture comprising at least afat or an oil with a high content of free fatty acids (a low quality oilor fat) is effective since the free fatty acids in the oil or fat act asa working fluid. Further, the free fatty acids in the oil or fat alsocontributes to an additive effect in the stripping process by partiallyacting as an internal working fluid (or by being an active part of theworking fluid) in the stripping process.

A person known in the art will also realise that the same strippingeffect can be obtained by adding a volatile working fluid containing asimilar volume of suitable free fatty acids to an oil or fat containingenvironmental pollutants in order to decrease the amount ofenvironmental pollutants in the fat or oil.

Example 10 Removal of Toxic Components From a Ricinus Oil

This example shows a process for decreasing the amount of toxiccompounds in a ricinus oil (castor oil, oil from the seeds of Ricinuscommunis L. Euphorbiaceae), which process comprises the steps of addinga volatile working fluid to a ricinus oil mixture and subjecting themixture, with the added volatile working fluid, to a moleculardistillation processing step, in which traces of ricinine from thericinus oil is separated from the mixture with the volatile workingfluid.

Firstly, 8% of a working fluid, (the ratio of (volatile workingfluid):(ricinus oil) is here about 8:100) a distilled fraction of ethylesters from a fish oil, was added to a ricinus oil prior to adistillation processing step. Secondly, the ricinus oil mixture wasdistilled in a molecular distillation process at a temperature of 170°C., at a pressure of 10⁻³ mbar and at a mixture flow of 500 ml/min. Theconcentration of toxic compounds were analysed before and aftertreatment. This analysis showed that the concentration of ricinine wassubstantially reduced compared to the concentration in the startingricinus oil. This shows that it is possible to reduce traces of toxiccomponents in a ricinus oil according to the invention, as long as theused volatile working fluid is essentially equally or less volatile thanthe components that is to be separated from the ricinus oil. Further,ricinus oil is used in both medicinal and cosmetic applications and thereduction of the existing trace levels of ricinin has commercial value.

1. A process for decreasing the amount of environmental pollutants in amixture comprising a fat or an oil, being edible or for use incosmetics, the fat or oil containing the environmental pollutants,characterized in that the process comprises the steps of; adding avolatile working fluid to the mixture, where the volatile working fluidcomprises at least one of a fatty acid ester, a fatty acid amide, a freefatty acid and a hydrocarbon, and subjecting the mixture with the addedvolatile working fluid to at least one stripping processing step, inwhich an amount of environmental pollutant present in the fat or oil,being edible or for use in cosmetics, is separated from the mixturetogether with the volatile working fluid.
 2. A process according toclaim 1, wherein the volatile working fluid is essentially equally orless volatile than the environmental pollutants that are to be separatedfrom the fat or oil mixture.
 3. A process according to claim 1, whereinthe volatile working fluid is constituted by free fatty acids comprisedin the fat or oil, being edible or for use in cosmetics, containing theenvironmental pollutants.
 4. A process according to claim 1, wherein theat least one of a fatty acid ester, a fatty acid amide and a free fattyacid is obtained from at least one of vegetable, microbial and animalfat or oil.
 5. A process according to claim 4, wherein the animal fat oroil is a fish oil and/or an oil obtained from sea mammals.
 6. A processaccording to claim 1, wherein the volatile working fluid comprises atleast one fatty acid ester composed of C10-C22 fatty acids and C1-C4alcohols, or a combination of two or more fatty acid ester each composedof C10-C22 fatty acids and C1-C4 alcohols.
 7. A process according toclaim 1, wherein the fat or oil, being edible or for use in cosmetics,is obtained from at least one of vegetable, microbial and animal fat oroil, or any combination thereof.
 8. A process according to claim 7,wherein the fat or oil, being edible or for use in cosmetics, is amarine oil.
 9. A process according to claim 8, wherein the marine oil isobtained from fish or sea mammals, containing at least saturated andunsaturated fatty acids in the form of triglycerides.
 10. A processaccording to claim 7, wherein the fat or oil is a ricinus oil for use incosmetics or medicinal applications.
 11. A process according to claim 7,wherein the fat or oil is a tocopherol concentrate prepared from acondensate from at least one deodorization process of at least onevegetable oil, wherein the tocopherol concentrate containing at leastone of PAH and volatile pollutants, or any combination thereof.
 12. Aprocess according to claim 1, wherein the ratio of (volatile workingfluid):(fat or oil, being edible or for use in cosmetics) is about 1:100to 15:100.
 13. A process according to claim 12, wherein the ratio of(volatile working fluid):(fat or oil, being edible or for use incosmetics) is about 3:100 to 8:100.
 14. A process according to claim 1,wherein said stripping processing step is carried out at temperatures inthe interval of 120-270° C.
 15. A process according to claim 1, whereinsaid stripping processing step is carried out at temperatures in theinterval of 150-200° C.
 16. A process according to claim 1, wherein saidstripping processing step is carried out at a pressure below 1 mbar. 17.A process according to claim 1, wherein the at least one strippingprocessing step is one of a thin-film evaporation process, a moleculardistillation or a short-path distillation or any combination thereof.18. A process according to claim 17, wherein the at least one thin-filmevaporation process is carried out at a mixture flow rate in theinterval of 10-300 kg/h m².
 19. A volatile environmental pollutantsdecreasing working fluid, for use in decreasing an amount ofenvironmental pollutants present in a fat or oil, being edible or foruse in cosmetics, the working fluid comprising at least one of a fattyacid ester, a fatty acid amide, a free fatty acid and a hydrocarbon, orany combination thereof.
 20. A volatile environmental pollutantsdecreasing working fluid according to claim 19, wherein said at leastone of a fatty acid ester, a fatty acid amide, a free fatty acid isobtained from at least one of vegetable, microbial and animal origin, orany combination thereof.
 21. A volatile fat or oil environmentalpollutants decreasing working fluid according to claim 20, wherein theanimal origin is fish or sea mammals.
 22. Use of a volatileenvironmental decreasing working fluid according to claim 19, in aprocess for decreasing an amount of environmental pollutants, such astoxic component, in a mixture comprising a fat or oil, being edible orfor use in cosmetics, preferably a marine oil, containing the toxiccomponents, in which process the volatile working fluid is added to themixture and then the mixture is subjected to at least one strippingprocessing step, preferably a thin-film evaporation process, a moleculardistillation or a short-path distillation, or any combination thereof,and in which process an amount of toxic components present in the fat oroil, being edible or for use in cosmetics, is separated from the mixturetogether with the volatile working fluid.
 23. A volatile environmentalpollutants decreasing working fluid, wherein the volatile working fluidis a by-product, such as a distillate fraction, from a regular processfor production of ethyl and/or methyl ester concentrates.
 24. A healthsupplement, containing at least a marine oil, which marine oil isprepared according to the process presented in claim 1, in order todecrease the amount of environmental pollutants in the marine oil.
 25. Apharmaceutical, containing at least a fish oil, which fish oil isprepared according to the process presented in claim 1, in order todecrease the amount of environmental pollutants in the fish oil.
 26. Ananimal feed product, containing at least a marine oil, which marine oilis prepared according to the process presented in claim 1, in order todecrease the amount of environmental pollutants respectively the amountof free fatty acids in the marine oil.
 27. An animal feed productaccording to claim 26, wherein the feed product is a fish feed product.28. A cosmetic product, based on ricinus oil, which ricinus oil isprepared according to the process presented in claim 1, in order todecrease the amount of environmental pollutants in the ricinus oil. 29.A marine oil product, prepared according to the process presented inclaim
 1. 30. A marine oil product according to claim 29, wherein themarine oil product is a fish oil product or a fish oil composition. 31.A tocopherol concentrate product, based on a tocopherol concentrateprepared from a condensate from a deodorization process of at least onevegetable fat or oil, such as palm oil or soy oil, which concentratecontaining at least one of PAH and volatile pollutants and is preparedaccording to the process presented in claim 1, in order to decrease theamount of PAH and volatile pollutants in the tocopherol concentrate.